Temporarily dontaudit ueventd->tmpfs access

This is the only blocker for SELinux denial test on microdroid. Rather
than consuming more time, this temporarily suppresses the audit message
to turn on the test.

Bug: 193118220
Test: atest MicrodroidHostTestCases -c
Change-Id: Id703107cbaae42352bebe34d0a6373f0701c0f6f
diff --git a/microdroid/system/private/ueventd.te b/microdroid/system/private/ueventd.te
index eb06672..4ff417b 100644
--- a/microdroid/system/private/ueventd.te
+++ b/microdroid/system/private/ueventd.te
@@ -50,3 +50,5 @@
 allow ueventd system_bootstrap_lib_file:dir r_dir_perms;
 allow ueventd system_bootstrap_lib_file:file { execute read open getattr map };
 
+# TODO(b/193118220): find out why this happens.
+dontaudit ueventd tmpfs:chr_file { relabelfrom setattr };